<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>text/html/value</title>
</head>
<body>
<div></div>

<input id="username"/>
</body>
<script src="../0.vendor/jquery-3.6.0.js"></script>
<script>

    /*1.插值*/
    $('div').text('hello');
    alert($('div').text());

    $('div').html('<h1>hello</h1>')
    $('div').html();

    $('#username').val('admin');
    $('#username').val();
</script>
</html>